MySQL从用户ID获取积分

Question

Note: new to mysql

I am trying to get points from user id ( please view attached table image)

qa_ is my custom table prefix

I am using wordpress and want to get current logged in user id and want to pass it so can get points of that user id.

Here what I am trying but nothing work

function qa_points($userid){
    global $wpdb;
    $prefix = 'qa_';
    $points = $wpdb->get_results("
        SELECT *
        FROM ${prefix}userpoints
        WHERE points = userid
    "); 

    return '(points '.$points['points'].')';

}

Answer 1

function qa_points($userid){
    global $wpdb;
    $prefix = 'qa_';
    $points = $wpdb->get_row("
        SELECT points
        FROM ".$prefix."userpoints
        WHERE userid = $userid
    "); 

    return '(points '.$points->points.')';

}

Answer 2

If you want to select the points from a user, you have to select the correct user:

$points = $wpdb->get_results("
        SELECT *
        FROM " . $prefix . "userpoints
        WHERE userid = $userid");